Page 713 of 5267

4.BATTERY TERMINAL CONNECTIONS
Visually inspect the positive and negative connections at the batteries and inspect the battery negative connections
at the engine block.
Are the connections free of corrosion and are they tight?
Ye s>>
Go To 5
No>>
Repair the poor connections.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
5.ACCESSORY WIRING
Check for add-on or accessory wiring at positive (+) terminal of the battery
Are there any damaged wires at the battery?
Ye s>>
Repair accessory wiring.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 6
6.BATTERY(S)
Perform battery load test using the Midtronics Micro 420 battery system tester.
Did the battery(s) pass the test?
Ye s>>
Go To 7
No>>
Replace the weak battery or batteries.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
7.HIGH RESISTANCE IN WIRE HARNESS
Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the battery terminals.
Measure the resistance from the positive and negative battery posts to
the appropriate circuits in the ECM harness connector
Is the resistance less than 10 Ohms?
Ye s>>
Go To 8
No>>
Repair the high resistance in the wire harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 715 of 5267
P0563-BATTERY VOLTAGE HIGH
For a complete wiring diagramRefer to Section 8W.
Page 718 of 5267
P0572-LOW VOLTAGE DETECTED AT THE BRAKE SWITCH
For a complete wiring diagramRefer to Section 8W.
Page 719 of 5267

When Monitored:
While the ignition is on
Set Condition:
The brake switch status is = to OFF and the not brake switch status is = to ON for a calibrated amount of
time..
Possible Causes
DAMAGED WIRING HARNESS OR CONNECTORS
BRAKE SWITCH CIRCUIT SHORTED TO GROUND (BRAKE SWITCH WILL ALWAYS BE OFF)
BRAKE SWITCH
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
1.BRAKE SWITCH CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the brake switch connection. Inspect the pins and connector
for damage, corrosion, etc.
Disconnect the ECM connectors. Inspect the pins and connector for
damage, corrosion, etc.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the brake switch circuit in the ECM
connector and battery negative.
Is the resistance less than 10 ohms?
Ye s>>
Repair the Brake switch circuit shorted to ground.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
No>>
Go To 2
Page 722 of 5267
P0573-HIGH VOLTAGE DETECTED AT THE BRAKE SWITCH
For a complete wiring diagramRefer to Section 8W.
Page 723 of 5267

When Monitored:
While the ignition is on.
Set Condition:
The brake switch status is = to ON and the not brake switch status is = to OFF for a calibrated amount of time.
Possible Causes
DAMAGED WIRING HARNESS OR CONNECTORS
BRAKE SWITCH CIRCUIT OPEN (BRAKE SWITCH WILL ALWAYS BE ON)
BRAKE SWITCH CIRCUIT SHORTED TO BATTERY VOLTAGE (BRAKE SWITCH WILL ALWAYSBE ON)
BRAKE SWITCH
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
1.BRAKE SWITCH CIRCUIT OPEN
Turn the ignition off.
Disconnect the brake switch connection. Inspect the pins and connector
for damage, corrosion, etc.
Disconnect the ECM connectors. Inspect the pins and connector for
damage, corrosion, etc.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the brake switch signal circuits in the
ECM connector and the brake switch connector.
Is the resistance less than 10 ohms?
Ye s>>
Go To 2
No>>
Repair the open brake switch circuits.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 725 of 5267
P0580-LOW VOLTAGE DETECTED AT THE SPEED CONTROL SWITCH
For a complete wiring diagramRefer to Section 8W.
Page 726 of 5267

When Monitored:
While the ignition is on
Set Condition:
Speed control MUX switch below 1.0 volts for 5 seconds.
Possible Causes
S/C WIRING HARNESS OBSERVABLE PROBLEM
S/C SWITCH (ON/OFF)
CLOCKSPRING SHORTED TO GROUND
S/C SWITCH (RESUME/ACCEL)
S/C SWITCH SIGNAL CIRCUIT SHORTED TO GROUND
S/C SIGNAL CIRCUIT SHORTED TO SENSOR GROUND
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.S/C SWITCH VOLTAGE BELOW 1.0 VOLT
Turn the ignition on.
With the scan tool, read the S/C Switch volts status in the ECM.
Is the S/C Switch voltage below 1.0 volt?
Ye s>>
Go To 3
No>>
Go To 2
2.S/C WIRING HARNESS OBSERVABLE PROBLEM
Turn the ignition off.
Using the Schematics as a guide, inspect the Wiring and Connectors.
Were any problems found?
Ye s>>
Repair as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 3
3.S/C SWITCH (ON/OFF)
Turn the ignition off.
Disconnect the S/C ON/OFF Switch harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Turn the ignition on.
With the scan tool in Sensors, read the S/C Switch volts in the ECM.
Did the S/C Switch volts change to 5.0 volts?
Ye s>>
Replace the S/C ON/OFF Switch.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 4